//isPrototypeOf用于检测此对象在不在指定对象原型链上

function MyConstructor(){

}
let myObj = new MyConstructor();
//判断MyConstructor.prototype在不在myObj的原型链上
console.log(MyConstructor.prototype.isPrototypeOf(myObj));//true
console.log(Object.prototype.isPrototypeOf(myObj));//true
console.log(MyConstructor.prototype.isPrototypeOf(new Object()));//false

